Laser Directed Energy Deposition (LDED) is transforming how we repair high-value components and build complex, near-net-shape metal parts. But the high thermal gradients involved can lead to nightmare scenarios: residual stress, warping, and cracks.
Digital simulation is the answer. Here is a guide to simulating the LDED Additive Manufacturing process on the 3DEXPERIENCE platform using the Additive Manufacturing Scenario Creation app.
1. The Workflow: From CAD to Virtual Twin
The process moves beyond simple toolpath generation. We are building a physics-based "Virtual Twin" of the printing process to predict defects before a single gram of powder is melted.
Step 1: Structural Model Creation (The Foundation)
Before defining the scenario, you must prepare the Finite Element (FE) model.
- Mesh: Create a voxel-based or standard mesh for the part and substrate.
- Material: Define temperature-dependent properties (conductivity, specific heat, elasticity) essential for accurate thermal-mechanical analysis.
Step 2: Scenario Setup (The Core)
Open the Additive Manufacturing Scenario Creation app. This is where the digital magic happens.
- Select Process Type: Choose Direct Material Deposition. This explicitly tells the solver (Abaqus) that material and heat are being added simultaneously.
- Define the Machine: Select your robot or CNC gantry setup from the library to check for reachability and collisions during the deposition.
- The "Event Series": This is the heartbeat of an LDED simulation. You don't just define a static load; you define a time-dependent deposition path.
Step 3: Physics & Activation Strategy
LDED simulation relies on Element Progressive Activation.
- How it works: Elements in the mesh are initially inactive. As the "Event Series" (laser path) intersects with the mesh, the app "activates" the elements, effectively simulating the bead deposition.
- Thermal Input: Apply a heat source model (e.g., Goldak or Concentrated) that follows the toolpath.
- Cooling: Don't forget to define convection and radiation coefficients for the cooling phases, which are critical for predicting residual stress.
Step 4: Sequential Simulation
The app typically runs a Sequential Thermal-Mechanical Simulation:
- Heat Transfer Analysis: Calculates the transient temperature history and melt pool dynamics.
- Structural Analysis: Uses the temperature history to calculate thermal expansion, contraction, and final residual stresses.
2. Analyzing the Results
Once the job is complete, switch to the Physics Results Explorer to validate your build.
- Temperature Field: Visualise the melt pool moving along the toolpath to ensure process stability.
- Distortion: Check if the part curls up from the substrate or warps out of tolerance.
- Residual Stress: Identify "hot spots" where cracking is likely to occur, allowing you to modify the scan strategy or add dwell times.
3. Why This Matters
By simulating LDED on 3DEXPERIENCE, you move from "Trial and Error" to "First Time Right." You can optimize laser power, scan speed, and deposition patterns virtually, saving thousands in wasted metal powder and machine time.
This video demonstrates the Additive Manufacturing Scenario app interface and workflow on the 3DEXPERIENCE platform; while it focuses on Powder Bed Fusion, the app's navigation, result visualization, and simulation setup logic are very similar to the LDED process described above.
